/// <summary>
/// Creates a button with a set of state-textures and (optionally) some text.
/// Any state that is left 'null' will display the up-state texture. Beware that all
/// state textures should have the same dimensions.
/// </summary>
/// <exception cref="ArgumentException">When upState is null</exception>
public Button(Texture upState, string text = "", Texture downState = null,
Texture overState = null, Texture disabledState = null)
{
if (upState == null)
{
throw new ArgumentException("Texture 'upState' cannot be null");
}
_upState = upState;
_downState = downState;
_overState = overState;
_disabledState = disabledState;
_state = ButtonState.Up;
_body = new Image(upState);
_body.PixelSnapping = true;
ScaleWhenDown = downState != null ? 1.0f : 0.9f;
ScaleWhenOver = AlphaWhenDown = 1.0f;
AlphaWhenDisabled = disabledState != null ? 1.0f : 0.5f;
_enabled = true;
_useHandCursor = true;
_textBounds = Rectangle.Create(0, 0, _body.Width, _body.Height);
_triggerBounds = Rectangle.Create();
_contents = new Sprite();
_contents.AddChild(_body);
AddChild(_contents);
Touch += OnTouch;
TouchGroup = true;
Text = text;
}
private void OnTouch(TouchEvent evt)
{
SparrowSharp.MouseCursor = (_useHandCursor && _enabled && evt.InteractsWith(this)) ? MouseCursor.Hand : MouseCursor.Default;
if (!_enabled)
{
return;
}
Touch touch = evt.GetTouch(this);
if (touch == null)
{
State = ButtonState.Up;
}
else if (touch.Phase == TouchPhase.Stationary)
{
State = ButtonState.Over;
}
else if (touch.Phase == TouchPhase.Began && _state != ButtonState.Down)
{
_triggerBounds = GetBounds(Stage);
_triggerBounds.Inflate(MaxDragDist, MaxDragDist);
State = ButtonState.Down;
}
else if (touch.Phase == TouchPhase.Moved)
{
var isWithinBounds = _triggerBounds.Contains(touch.GlobalX, touch.GlobalY);
if (_state == ButtonState.Down && !isWithinBounds)
{
// reset button when finger is moved too far away ...
State = ButtonState.Up;
}
else if (_state == ButtonState.Up && isWithinBounds)
{
// ... and reactivate when the finger moves back into the bounds.
State = ButtonState.Down;
}
}
else if (touch.Phase == TouchPhase.Ended && _state == ButtonState.Down)
{
State = ButtonState.Up;
Triggered?.Invoke(this, evt);
}
}